org.wicketstuff.jeeweb.ajax.JEEWebGlobalAjaxHandler.java Source code

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Here is the source code for org.wicketstuff.jeeweb.ajax.JEEWebGlobalAjaxHandler.java

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/**
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.wicketstuff.jeeweb.ajax;

import java.util.ArrayList;
import java.util.List;

import org.apache.wicket.Application;
import org.apache.wicket.Page;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.WicketAjaxJQueryResourceReference;
import org.apache.wicket.event.Broadcast;
import org.apache.wicket.markup.head.HeaderItem;
import org.apache.wicket.markup.head.IHeaderResponse;
import org.apache.wicket.markup.head.JavaScriptHeaderItem;
import org.apache.wicket.markup.html.IHeaderContributor;
import org.apache.wicket.protocol.http.WebApplication;
import org.apache.wicket.protocol.http.WebSession;
import org.apache.wicket.request.Url;
import org.apache.wicket.request.cycle.PageRequestHandlerTracker;
import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.mapper.parameter.PageParameters;
import org.apache.wicket.request.resource.IResource;
import org.apache.wicket.request.resource.JavaScriptResourceReference;
import org.apache.wicket.request.resource.ResourceReference;
import org.apache.wicket.util.string.Strings;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This class is used to configure a global ajax event hook for the embedded tags (Servlet, JSP,
 * JSF). The tag libs can be used to generate a callback function to send an ajax request to the
 * current rendered page / their components<br>
 * <br>
 * 
 * <b>WATCH OUT - The WebPage has to be configured with setStatelassHint(false); !!!!
 * 
 * The ajax functions are in the ELFunctions class beginning with ajax...
 * 
 * @see org.wicketstuff.jeeweb.el.ELFunctions
 * 
 * @author Tobias Soloschenko
 *
 */
public class JEEWebGlobalAjaxHandler extends ResourceReference {

    private static final Logger LOGGER = LoggerFactory.getLogger(JEEWebGlobalAjaxHandler.class);

    private static final long serialVersionUID = 4348780269907263872L;

    public JEEWebGlobalAjaxHandler() {
        super(JEEWebGlobalAjaxHandler.class.getSimpleName());
    }

    /**
     * Receives ajax events and delegates them to the page which where rendered previously.
     */
    @Override
    public IResource getResource() {
        return new IResource() {
            private static final long serialVersionUID = 3070290312369930992L;

            @Override
            public void respond(Attributes attributes) {
                try {
                    PageParameters parameters = attributes.getParameters();

                    int pageId = parameters.get("pageId").toInt();
                    Page page = (Page) WebSession.get().getPageManager().getPage(pageId);
                    AjaxRequestTarget newAjaxRequestTarget = ((WebApplication) Application.get())
                            .newAjaxRequestTarget(page);
                    RequestCycle.get().scheduleRequestHandlerAfterCurrent(newAjaxRequestTarget);
                    page.send(page, Broadcast.BREADTH, new JEEWebGlobalAjaxEvent(newAjaxRequestTarget, parameters,
                            RequestCycle.get().getRequest().getPostParameters()));
                } catch (Exception e) {
                    LOGGER.error("Error while processing the ajax request", e);
                }
            }
        };
    }

    /**
     * Configures the handler to the given application.
     * 
     * @param application
     *            the application to configure the handler to
     */
    public static void configure(WebApplication application) {
        application.getRequestCycleListeners().add(new PageRequestHandlerTracker());
        application.mountResource("/" + JEEWebGlobalAjaxHandler.class.getSimpleName(),
                new JEEWebGlobalAjaxHandler());
        application.getHeaderContributorListeners().add(new IHeaderContributor() {

            private static final long serialVersionUID = 1644041155625458328L;

            @Override
            public void renderHead(IHeaderResponse response) {
                JavaScriptResourceReference forReference = new JavaScriptResourceReference(
                        JEEWebGlobalAjaxHandler.class, JEEWebGlobalAjaxHandler.class.getSimpleName() + ".js") {

                    private static final long serialVersionUID = -3649384632770480975L;

                    @Override
                    public List<HeaderItem> getDependencies() {
                        return new ArrayList<HeaderItem>() {
                            private static final long serialVersionUID = 1L;
                            {

                                add(JavaScriptHeaderItem.forReference(WicketAjaxJQueryResourceReference.get()));
                            }
                        };
                    }
                };
                response.render(JavaScriptHeaderItem.forReference(forReference));
                addAJaxBaseUrl(response);
            }

            private void addAJaxBaseUrl(IHeaderResponse response) {
                // render ajax base url. It's required by Wicket Ajax support.
                Url baseUrl = RequestCycle.get().getUrlRenderer().getBaseUrl();
                CharSequence ajaxBaseUrl = Strings.escapeMarkup(baseUrl.toString());
                response.render(JavaScriptHeaderItem.forScript("Wicket.Ajax.baseUrl=\"" + ajaxBaseUrl + "\";",
                        "wicket-ajax-base-url"));

            }
        });
    }
}